Telephone transactions are often used by consumers to obtain extensions of credit, make payment of debts, perform fund transfers, and order products from catalogs. Typically such transactions are carried out by a user with a touch-tone telephone, who enters a telephone number to access a service and enters numbers relating to the service such as credit card numbers or menu selections, from the telephone keypad after obtaining access.
Touch tones are the dual tone multi-frequency signals ("DTMF" tones), generated as the user enters numbers from the keypad. In accordance with the DTMF technique used to generate touch tone signals, a touch tone signal is produced by generating two tones, one tone being selected from a high frequency band group and the other being selected from a low frequency band group. Each of the low frequency tones corresponds to one of the four rows of keys on a standard telephone keypad, while each one of the four high frequency tones corresponds to one of the four columns of keys on a standard extended telephone keypad. A standard telephone keypad typically has three columns, but can be extended, as the tones generated by a fourth column are recognized by most central office receivers. In telephone transactions, the touch tones typically represent a number or character that corresponds to user-information (e.g., entering numbers that represent a credit card number, entering letters that represent a surname) or service selections (e.g., entering a "1" to choose a list of products offered, versus entering a "0" to order products).
Although telephone transactions afford convenience to those who use them, they are often wrought with security problems. For example, a person viewing or overhearing the initiation of a telephone transaction can record a credit card number entered through the telephone keypad or spoken into the handset microphone. The recorded credit card number is later, and often undetectably, used to carry out fraudulent transactions by unauthorized individuals. Similarly, a person overhearing or viewing another entering a personal identification number (`pin`) can use the pin to access, and often deplete or use, such accounts as one's bank account or telephone calling card account, with the account holder discovering the theft only after the damage has been done.
While portable electronic information cards have attempted to solve the problem by providing a system that can be acoustically coupled to a telephone system, the data transmission errors and security problems inherent in such cards has inhibited widespread acceptance and use of them. Security problems such as pin detection remain common, particularly when one uses the card with a cellular phone. Moreover, errors associated with such cards are often due to the necessary acoustic couplings associated therewith. Also common are errors due to temperature variations affecting battery voltages, amplification levels applied to DTMF signals, speaker proximity to a telephone handset's microphone, distortions introduced by the microphone receiving DTMF tones, and ambient noise. Although promising a measure of convenience and privacy, the implementation of electronic information cards has brought about a host of new problems without significantly alleviating or solving many existing security problems associated with telephone transactions.
As the accuracy and security associated with telephone transactions is often compromised, there exists a need for a system capable of maintaining the flexibility and convenience inherent in telephone transactions, while not comprising the privacy and security necessary to prevent the occurrence of fraudulent transactions.
The present invention provides a user-authentication system that avoids the above-noted problems, while improving signal transmission, signal routing, and system security.